Single-package wireless communication device

ABSTRACT

A method, apparatus and system with an autonomic, self-healing polymer capable of slowing crack propagation within the polymer and slowing delamination at a material interface.

CLAIM OF PRIORITY

This application is a divisional of U.S. patent application Ser. No.12/714,718, now U.S. patent Ser. No. ______, which was filed on Mar. 1,2010 and which is a divisional of U.S. patent application Ser. No.11/394,831, now U.S. Pat. No. 7,692,295, which was filed on Mar. 31,2006.

TECHNICAL FIELD

The invention relates to the field of microelectronics and moreparticularly, but not exclusively, to packaging wireless communicationsdevices.

BACKGROUND

The evolution of integrated circuit designs has resulted in higheroperating frequency, increased numbers of transistors, and physicallysmaller devices. This continuing trend has generated ever increasingarea densities of integrated circuits and electrical connections. Thetrend has also resulted in higher packing densities of components onprinted circuit boards and a constrained design space within whichsystem designers may find suitable solutions. Physically smaller deviceshave also become increasingly mobile.

At the same time, wireless communication standards have proliferated ashas the requirement that mobile devices remain networked. Consequently,many mobile devices include a radio transceiver capable of communicatingaccording to one or more of a multitude of communication standards. Eachdifferent wireless communication standard serves a different type ofnetwork. For example, a personal area network (PAN), such as Blue Tooth(BT), wirelessly maintains device connectivity over a range of severalfeet. A separate wireless standard, such as IEEE 802.11a/b/g (Wi-Fi),maintains device connectivity over a local area network (LAN) thatranges from several feet to several tens of feet.

A typical radio transceiver includes several functional blocks spreadamong several integrated circuit packages. Further, separate packagesoften each contain an integrated circuit designed for a separate purposeand fabricated using a different process than that for the integratedcircuit of neighboring packages. For example, one integrated circuit maybe largely for processing an analog signal while another may largely befor computationally intense processing of a digital signal. Thefabrication process of each integrated circuit usually depends on thedesired functionality of the integrated circuit, for example, an analogcircuit generally is formed from a process that differs from that usedto fabricate a computationally intense digital circuit. Further,isolating the various circuits from one another to preventelectromagnetic interference may often be a goal of the designer. Thus,the various functional blocks of a typical radio transceiver are oftenspread among several die packaged separately.

Each package has a multitude of power, ground, and signal connectionswhich affects package placement relative to one another. Generally,increasing the number of electrical connections on a package increasesthe area surrounding the package where trace routing density does notallow for placement of other packages. Thus, spreading functional blocksamong several packages limits the diminishment in physical size of theradio transceiver, which in turn limits the physical size of the devicein which the radio transceiver is integrated.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates a block diagram of a prior art radio transceiverapplication.

FIG. 2 illustrates a block diagram of an exemplary single package radiotransceiver application.

FIG. 3 illustrates a cross-sectional view of an exemplary single packageradio transceiver.

FIG. 4 illustrates (1) an exemplary array of solder balls for coupling asingle package radio transceiver to a printed circuit board and (2) anexemplary array of solder pads on a printed circuit board to which asingle package radio transceiver may be coupled.

FIG. 5 illustrates an embodiment of a method of packaging a singlepackage radio transceiver.

FIG. 6 illustrates a system schematic that incorporates an embodiment ofa single package radio transceiver.

DETAILED DESCRIPTION

Herein disclosed are a package, a method of packaging, and a systemincluding the package for an integrated, multi-die radio transceiver.

In the following detailed description, reference is made to theaccompanying drawings which form a part hereof wherein like numeralsdesignate like parts throughout, and in which is shown, by way ofillustration, specific embodiments in which the invention may bepracticed. Other embodiments may be utilized, and structural or logicalchanges may be made, without departing from the intended scope of theembodiments presented. It should also be noted that directions andreferences (e.g., up, down, top, bottom, primary side, backside, etc.)may be used to facilitate the discussion of the drawings and are notintended to restrict the application of the embodiments of thisinvention. Therefore, the following detailed description is not to betaken in a limiting sense and the scope of the embodiments of thepresent invention is defined by the appended claims and theirequivalents.

DESCRIPTION OF A RADIO TRANSCEIVER

Please refer to FIG. 1 for a functional block diagram of a typical priorart radio transceiver application.

A typical radio transceiver usually includes several separate functionalblocks, including a Front End Module (FEM) 106, a Radio FrequencyIntegrated Circuit (RFIC) 108, and a Base Band/Communication Processor112, that electrically couple to application specific circuitry 118. Thetypical radio transceiver spreads the several functional blocks amongdifferent die and integrated circuit packages. The FEM 106 generallyprocesses a radio frequency (RF) signal collected from an antenna 104.The FEM 106 may include a low noise amplifier for small signal receivergain larger than about 90 dB or a power amplifier for output power inexcess of about 17 dBm or about 50 mW, and passive frequency selectioncircuits. The FEM 106 processes the RF signal before communicating asignal to the RFIC 108 for mixed signal processing. The RFIC 108 usuallyconverts the RF signal from the FEM 106 to a digital signal and passesthe digital signal to a Base Band/Communication Processor 112. The BaseBand/Communication Processor 112 generally communicates with applicationspecific circuitry 118 that often includes an application processor 122coupled to user interface peripherals 126 and a system memory 120. Insome instances, the Base Band/Communication Processor 112 is coupled toa memory 110 which may be on a separate die, or integrated into the dieof the Base Band/Communication Processor 112. Power consumption for theapplication processor may be managed by power management circuitry 124.The RFIC 108 may also receive a signal input gathered from a GlobalPositioning System Receiver (GPS Receiver) 114.

The FEM 106 and RFIC 108 are often on different die because offunctional differences between the circuits that may not be easilyachieved through the same die fabrication process. The BaseBand/Communication Processor 112 may typically perform computationallyintensive operations and therefore be fabricated using yet anotherprocess that differs from either of those used to fabricate the FEM 106or the RFIC 108. Further, the different die will often be packagedseparately, although some prior art radio transceivers have integratedthe FEM 106 and RFIC 108 within the same package, as indicated by thePrior Art Wireless Integration block 102. Usually, the GPS Receiver 114will also be packaged separately from other die. Further, the referenceoscillator (crystal) 116 will generally be in a different package due toits sensitivity to temperature variance.

Current packages that integrate the FEM 106 and RFIC 108 use arrays ofsolder bumps on the individual die to couple the die to a packagesubstrate. Further, the die are each disposed on the substrate in asubstantially two-dimensional layout. A radio frequency transceiverintegrated in a single package may address many shortcomings of presentradio frequency transceivers. Because the different die will often bepackaged separately, current system costs will often be higher than ifthe various die could be included in a single package. Further, becausepresent systems continue to evolve to smaller form factors, a radiofrequency transceiver integrated into a single package may help a systemdesigner to achieve a desired overall system size that by itself issmaller than a radio frequency transceiver spread among severalpackages.

Integration of a Radio Transceiver in a Single Package

FIG. 2 illustrates a functional block diagram of a system 200 using aradio frequency transceiver 202 wherein the radio frequency transceiver202 is integrated into a single integrated circuit package, shown as 300in FIG. 3 and further described below. The radio frequency transceiver202 includes an antenna 204, an FEM (analog) 206, an RFIC (mixedanalog/digital) 208, and a Base Band/Communication Processor (digital)212. The reference oscillator (crystal) 216 resides outside theintegrated circuit package 300 because of its sensitivity to temperatureand mechanical stress, both of which are often unavoidable duringpackage assembly. Some embodiments of the radio frequency transceiver202 also include a memory 210 coupled to the Base Band/CommunicationProcessor 212. Other embodiments of the radio frequency transceiver 202may be capable of receiving input from other types of receivers, forexample, a global positioning system receiver 214. The signal collectedby the alternative receiver 214 is transmitted to the RFIC 208. Thedigital output of the Base Band/Communication Processor 212 couples toan application specific integrated circuit 218 that includes anapplication processor 222. Further, the application processor 222couples to a memory 220, power management circuitry 224, and anyperipherals 226. The peripherals 226 often include one or more of thefollowing: an input/output interface, a user interface, an audio, avideo, and an audio/video interface.

The application processor 222 often defines the standard used by theradio frequency transceiver 202. Exemplary standards may include, by wayof example and not limitation, a definition for a personal area network(PAN), such as Blue Tooth (BT), that wirelessly maintains deviceconnectivity over a range of several feet, a local area network (LAN)that ranges from several feet to several tens of feet such as IEEE802.11a/b/g (Wi-Fi), a metropolitan area network (MAN) such as (Wi-Max),and a wide area network (WAN), for example a cellular network.

An exemplary embodiment of a package 300 that integrates a radiofrequency transceiver 202 is illustrated by FIG. 3 and utilizes diestacking, or packaging in a third dimension, to alleviate many of theaforementioned problems, such as limited diminishment in size andincreased packaging costs, associated with prior art two-dimensionallayouts. The integrated radio frequency transceiver 202 in a singlepackage 300 includes an antenna 204 formed by a copper stud 322 and astack of a first die 306 and a second die 310 coupled to the packagesubstrate 328, to which is also coupled a third die 302.

In the embodiment of FIG. 3 , the third die 302 forms a front end module206 and is coupled to the substrate 328 though solder bumps 304. Thethird die may be formed substantially of gallium arsenide, silicon onsapphire, or silicon germanium. The second die 310 forms a BaseBand/Communication Processor 210 and mechanically couples to the firstdie 306 that includes a radio frequency integrated circuit (RFIC) 208.The first die 306 is electrically coupled to the substrate 328, oftenthrough solder bumps 308. For first die 306 sizes less thanapproximately 3.5 mm×3.5 mm underfill may often not be used. Largerfirst die 306 may utilize underfill. The second die 310 is electricallycoupled to the substrate 328 through wire bonds 312. One method ofmechanically coupling the first die 306 and second die 310 includesusing an interface bonding agent 314, for example an epoxy. Manyinterface bonding agents 314 other than epoxy are known, e.g., RTVrubbers. The package 300 includes an antenna 204 formed of a copper stud322 that couples to a package cover 334 that may act also as a heatspreader. Also included in the embodiment illustrated by FIG. 3 is afourth die 316 on which is formed memory 210. The fourth die 316 couplesto the circuitry of the second die 310 through a direct chip attachformed of solder bumps 318 and underfill 320. Some embodiments ofunderfill 320 may include an adhesive tape or epoxy. Passive components330 and 332, such as inductor based components used for tuning, may belocated at convenient locations on the substrate 328 if they are notincluded in the die 306 including the RFIC 208. The passive components330 and 332 may include high speed switching components formed ondepleted CMOS devices, thereby enabling reconfigurable adaptive passivecircuits. The package substrate 328 may have solder mask defined padsfor surface mount components, and immersion gold plating may be used onthe pads.

The embodiment of the package 300 shown includes an array of solderballs 326 that may be used to electrically and mechanically couple thepackage 300 to a printed circuit board (not shown). Some of the solderballs 326 may be arranged in groups 324 that will collapse and coalesceduring reflow, and form a large area connection convenient for groundingthe package 300. FIG. 4 illustrates a substrate 402 of a package 400with an array of signal solder balls 404 and an array of ground solderballs 408. The signal solder balls are distributed using a ball to ballpitch 406 that maintains the integrity of each solder ball 404. Thesolder balls 408 used for grounding are distributed with a narrowerpitch 410 such that on reflow the balls coalesce to form a larger areaconnection. The embodiment shown by FIG. 4 includes solder balls 412that may be used for power, ground, additional signals, or merelyadditional structural support without any electrical connectivity. Aprinted circuit board 414 may include arrays of exposed pads 416 and 418similar to the arrays of solder balls. For example, the pitch 420between exposed pads for the signals may be substantially similar to thepitch 406 for the signal solder balls 404. Ground pads 418 may be asingle large area of exposed metal, or an array of large exposed areas,similar to those shown. The substrate 414 may have outer metal layerthicknesses of approximately 35 μm and inner metal layer thicknessranging from approximately 60 μm to 150 μm.

A Single Package Radio Transceiver Assembly Method

FIG. 5 illustrates an exemplary method of integrating a multiple die ina single integrated circuit package. The method illustrated may be usedto package a combination of die wherein some of the die forming theradio transceiver are stacked and form a three dimensional integration.For example, the method of FIG. 5 includes soldering a first die to apackage substrate having a layer of electrical traces and another layerof dielectric material 502. A method similar to one illustrated by FIG.5 also includes mechanically coupling a second die to the first 504. Toachieve a functional die stack, wire bonds electrically couple thesecond die to the package substrate 506.

As mentioned, the method illustrated by FIG. 5 results in asubstantially integrated radio frequency transceiver. The methodillustrated by FIG. 5 may be used to form a radio frequency transceivercapable of communicating according to any of a multitude of wirelessstandards that cover operation of networks ranging from personal areanetworks or local area networks to metropolitan area networks or widearea networks. Consequently, FIG. 5 illustrates forming an antennaelectrically coupled to the substrate 508 and soldering a third die tothe substrate, wherein the antenna, first, second, and third diesubstantially form a radio transceiver 510. The third die will often besubstantially formed of gallium arsenide, silicon on sapphire, orsilicon germanium, although other materials may often work as well.

In a radio frequency transceiver of the type whose assembly process isillustrated by FIG. 5 , the second die substantially forms the oftenheavily computational, digital circuits of a base band communicationprocessor. Some embodiments of a radio frequency transceiver couplememory to the digital circuits of the base band communication processor.Some of those embodiments may use a separate die for the memory andcouple the memory die to the second die that substantially includes thedigital circuits of the base band communications processor. A method ofassembly, as illustrated by FIG. 5 , may couple the memory die to thesecond die prior to mechanically coupling the second die to the firstdie 512.

Further, radio frequency transceivers may often benefit from groundingthrough large area electrical ground connections. As described above,such connections may form when two or more solder balls collapse andcoalesce during reflow and form an electrical connection with largercross-sectional area than a single constituent solder ball 514.

A System Embodiment that Includes a Single Package Radio Transceiver

FIG. 6 illustrates a schematic representation of one of many possiblesystems 60 that incorporate an embodiment of a single package radiotransceiver 600. In an embodiment, the package containing a radiofrequency transceiver 600 may be an embodiment similar to that describedin relation to FIG. 3 . In another embodiment, the package 600 may alsobe coupled to a sub assembly that includes a microprocessor. In afurther alternate embodiment, the integrated circuit package may becoupled to a subassembly that includes an application specificintegrated circuit (ASIC). Integrated circuits found in chipsets (e.g.,graphics, sound, and control chipsets) or memory may also be packaged inaccordance with embodiments described in relation to a microprocessorand ASIC, above.

For an embodiment similar to that depicted in FIG. 6 , the system 60 mayalso include a main memory 602, a graphics processor 604, a mass storagedevice 606, and an input/output module 608 coupled to each other by wayof a bus 610, as shown. Examples of the memory 602 include but are notlimited to static random access memory (SRAM) and dynamic random accessmemory (DRAM). Examples of the mass storage device 606 include but arenot limited to a hard disk drive, a flash drive, a compact disk drive(CD), a digital versatile disk drive (DVD), and so forth. Examples ofthe input/output modules 608 include but are not limited to a keyboard,cursor control devices, a display, a network interface, and so forth.Examples of the bus 610 include but are not limited to a peripheralcontrol interface (PCI) bus, PCI Express bus, Industry StandardArchitecture (ISA) bus, and so forth. In various embodiments, the system60 may be a wireless mobile phone, a personal digital assistant, apocket PC, a tablet PC, a notebook PC, a desktop computer, a set-topbox, an audio/video controller, a DVD player, a network router, anetwork switching device, a hand-held device, or a server.

Although specific embodiments have been illustrated and described hereinfor purposes of description of an embodiment, it will be appreciated bythose of ordinary skill in the art that a wide variety of alternateand/or equivalent implementations calculated to achieve similar purposesmay be substituted for the specific embodiments shown and describedwithout departing from the scope of the present disclosure. For example,a processor and chipset may be integrated within a single packageaccording to the package embodiments illustrated by the figures anddescribed above, and claimed below. Alternatively, chipsets and memorymay similarly be integrated, as may be graphics components and memorycomponents.

Those with skill in the art will readily appreciate that the descriptionabove and claims below may be implemented using a very wide variety ofembodiments. This detailed description is intended to cover anyadaptations or variations of the embodiments discussed herein.Therefore, it is manifestly intended that this invention be limited onlyby the claims and the equivalents thereof.

1.-13. (canceled)
 14. A system comprising: a first die coupled to a substrate, the first die including a radio frequency integrated circuit; a second die including a base band communication processor stacked on top of the first die; an antenna coupled to the substrate; and a third die including a front end module for processing radio frequency signals, coupled to the antenna.
 15. The system of claim 14, wherein the third die further includes a low noise amplifier.
 16. The system of claim 14, wherein the third die further includes a power amplifier.
 17. The system of claim 14, wherein the third die further includes a switch.
 18. The system of claim 14, wherein the third die includes gallium arsenide.
 19. The system of claim 14, wherein the third die includes silicon-on-sapphire.
 20. The system of claim 14, wherein the third die includes silicon germanium.
 21. A system comprising: a first die coupled to a substrate, the first die including a radio frequency integrated circuit; a second die including a base band communication processor stacked on the first die; an antenna coupled to the substrate; a third die including a front end module for processing radio frequency signals, coupled to the antenna; and a fourth die stacked on the second die, the fourth die including a memory device.
 22. The system of claim 21, wherein the fourth die is electrically coupled to the third die through an array of solder bumps.
 23. The system of claim 21, wherein the second die is mechanically coupled to the first die using an interface bonding agent.
 24. The system of claim 21, wherein the antenna includes a copper stud.
 25. The system of claim 21, further comprising: an application processor coupled to the base band communication processor; a memory coupled to the application processor; and an input/output interface coupled to the application processor.
 26. The system of claim 21, further including a global positioning system coupled to the first die.
 27. A method comprising: coupling a first die to a substrate, the first die including a radio frequency integrated circuit; stacking a second die on top of the first die, the second die including a base band communication processor; coupling an antenna to the substrate; and coupling a third die to the antenna, the third die including a front end module for processing radio frequency signals.
 28. The system of claim 27, wherein the third die further includes a low noise amplifier.
 29. The system of claim 27, wherein the third die further includes a power amplifier.
 30. The system of claim 27, wherein the third die further includes a switch.
 31. The system of claim 27, wherein the third die includes gallium arsenide.
 32. The system of claim 27, wherein the third die includes silicon-on-sapphire.
 33. The system of claim 27, wherein the third die includes silicon germanium. 